Hey, got the same issue and fairly the same setup:
K8N NEO4 Platinum
Athlon64 3200+
2x500 pc3200 DDR400 ADATA
GeForce 6600GT
10000rpm seagate 40gb
7200rpm seagate 160gb
At first I would have suggested u change to 2 similar mem-modules, but u say u tried without one of them so that probably isn't the problem. Try moving it around (using just one of them).
Now, as you post, it shuts down randomly, driving me nutz!
It even shuts down when i'm in the bios-setup!!!
I tried the following:
Ran checkdisk on all partitions.
Virus scanned the discs.
Used adaware and spybot to scan for trojans.
Upgraded and downgraded all gfx drivers.
Upgraded winXP and every other driver i can think of.
Unplugged the memory modules one at a time.
Unplugged the second hd.
Unplugged both DVD/CD-RW drives.
Unplugged external fans.
I've checked the heat (cpu 39 celsius, system temp the same) and all fan speeds.
Measured power outlets as well as internal 12V connectors.
Run with open/closed case, connected more/less fans.
FINALLY, I LOST IT AND FLASHED THE BIOS, crossing fingers and toes it wouldn't shutdown during the process, and... it didn't.
Result? Nothing. It still shuts down.
It tends to shut down more easily when playing games, and once it has, it will go on until (and this is my best shot) the power supply cools off.
So what I'm gonna do is swap my lousy no-name 400w power supply for an R-type 580w - I'm almost sure this is the problem, the power supply gets hot, and unstable, and cant deliver enough to keep the computer running.
Also, a tip: right click on my computer, props, advanced, turn off "shutdown on error" or whatever it says. If u have a software problem, windows will tell you about it before shutting down. This didnt help me, it keeps "dying" without warning, so i figured this has to be hardware related.
It gets down to this:
If it isn't the power supply, it has to be the gfxcard. Sometimes the gfxcard can generate some weird errors.
I hope u get some ideas at least, and if you ever fix your problem, please repost and maybe i'll solve mine too. I'll be sure to do the same if I have a miracle :lol:
/ DESPERATE - AND BROKE, OR I WOULD THROW THE DAMN THING OUT THE WINDOW
my system shuts down on it's own free will...sometimes i get a few hours of run time, other times i get a few seconds..i haven't updated the bios for fear of it shutting down half way through the update..it will shut down at post, or while running windows...problem seems worse during game play but the CPU temp stays around 49 degrees C.....so far i've put Dynex Silver cooling compound on the CPU using factory heatsink/fan. This system is running at factory speeds..i have not tried OC'ing or changing any CPU or other system chip settings...i've tried different sticks of memory thinking that could be the issue..i've diconnected different components (hard drives, cd players add in cards etc) my only thought is the CPU itself is bad...i'm hoping it's not the cpu or MOBO...if anyone could help me out it would be great.
System specs:
MSI K8N Neo4 Platinum/SLI
AMD Athlon 64 3200+ Venice core
Buffalo DDR 400 (pc3200) 512mb
SMT DDR266 (pc2700) 512mb (tried system w/o this stick as well)
ATI Radeon x1300pro 256